Dog's Mercury prefers consistently moist soil but dislikes waterlogging. Water thoroughly when the top few centimeters of soil feel dry, particularly during dry spells.

Reduce watering in winter, allowing the soil to dry out slightly between waterings. Overwatering can lead to root rot, so ensure good drainage.

Pruning is typically minimal for Dog's Mercury. Remove any dead or damaged foliage in late winter or early spring to tidy the plant.

If the plant becomes too sprawling, light trimming can be done after flowering to maintain shape. Avoid heavy pruning as it can disrupt its natural growth habit.

Mercurialis perennis is easily propagated by division of clumps in early spring or autumn. Seeds can also be sown fresh in autumn outdoors.

It readily self-seeds, often spreading to form dense patches, which can be managed by transplanting seedlings or dividing established plants.

Repotting is rarely necessary for Mercurialis perennis, as it thrives when left undisturbed and often spreads naturally.

If a container-grown specimen becomes root-bound or needs rejuvenation, repot in early spring into a slightly larger pot with fresh, well-draining soil. Division is a more common way to manage its spread.